Many useful clinical trials needed to answer important questions are not performed because there is a financial disincentive to perform clinical trials having a significant likelihood of demonstrating that an expensive therapy is unnecessary. Single-site and multicenter clinical trials are also disincentivized when the cost of making them well controlled and sufficiently powered is high, in terms of required work effort, clinician experience, and funding. Furthermore, important clinical trials will not be funded by pharmaceutical or medical device corporations if there are insufficient financial incentives to do so.